condition mean min max ZT0-3 18.010138 18.010138 18.010138 ZT4-7 22.786534 22.786534 22.786534 ZT8-11 19.958254 19.958254 19.958254 ZT12-15 20.040955 20.040955 20.040955 ZT16-19 19.240833000000002 19.240833000000002 19.240833000000002 ZT20-23 17.220906 17.220906 17.220906